The AXIN1 Knockout HAP1 Polyclonal Cells are a CRISPR/Cas9-edited polyclonal knockout cell population derived from the HAP1 human chronic myeloid leukemia near-haploid cell line. This product features a targeted disruption of the AXIN1 gene, resulting in loss of AXIN1 protein function and providing a versatile model for studying Wnt/??-catenin signaling and related pathways. The polyclonal format comprises a heterogeneous mix of edited alleles, eliminating the need for single-cell cloning and enabling robust loss-of-function analyses across a representative cellular pool.
HAP1 cells are a male-derived adherent fibroblast-like cell line with a near-haploid karyotype, originally isolated from the KBM-7 chronic myeloid leukemia line. The near-haploid genome simplifies genetic manipulation and phenotypic interpretation, as gene disruption generally affects the single remaining allele, minimizing complexities from heterozygous expression. HAP1 cells have been extensively validated for CRISPR-based functional genomics, high-throughput screening, and signal transduction studies, making them an ideal host for targeted knockout models such as this AXIN1-deficient population.
AXIN1 encodes a critical scaffold protein of the ??-catenin destruction complex, functioning as a negative regulator of canonical Wnt/??-catenin signaling. In the absence of Wnt ligands such as WNT3A, AXIN1 assembles a multi-protein complex containing APC, GSK3??, and CK1??, which phosphorylates ??-catenin (CTNNB1) at Ser33/Ser37/Thr41, targeting it for ubiquitination and proteasomal degradation. Upon pathway activation by WNT3A binding to FZD1 and LRP6, DVL2 recruitment leads to AXIN1 complex disassembly, allowing ??-catenin to stabilize, translocate to the nucleus, and interact with TCF/LEF transcription factors including TCF7L2 to drive expression of pro-proliferative genes such as MYC and CCND1. AXIN1 also integrates signals from Hippo/YAP, mTOR, TGF-??, and p53 pathways, interacting with proteins such as SMAD3, PP2A, and tankyrase (TNKS1). Disruption of AXIN1 impairs destruction complex integrity, causing constitutive ??-catenin accumulation and aberrant transcriptional activation.
In the near-haploid HAP1 background, CRISPR/Cas9-mediated AXIN1 disruption creates a powerful model for dissecting Wnt/??-catenin signaling with minimal compensatory effects from redundant alleles. The polyclonal nature ensures a range of loss-of-function alleles are represented, facilitating robust detection of functional phenotypes without clonal selection bias. This model is particularly valuable for investigating AXIN1??s tumor-suppressive roles, as inactivating mutations are frequent in hepatocellular carcinoma, colorectal cancer, and medulloblastoma. The HAP1 system enables direct correlation between AXIN1 loss and ??-catenin-driven transcriptional output, providing a streamlined platform for mechanistic studies and drug target validation in a hematologic context.
This AXIN1 knockout population is suitable for a broad spectrum of functional studies, including Western blotting for AXIN1 and ??-catenin, RT-qPCR of Wnt target genes (e.g., MYC, CCND1), and ??-catenin transcriptional reporter assays (TOP/FOP Flash). Co-immunoprecipitation experiments can be used to assess destruction complex integrity, while immunofluorescence analyses reveal ??-catenin nuclear localization upon AXIN1 loss. Cell proliferation assays and flow cytometry-based cell cycle profiling enable quantitative assessment of growth deregulation, and drug sensitivity screens can identify compounds that selectively inhibit AXIN1-deficient cells. Additionally, the polyclonal HAP1 AXIN1 knockout model supports large-scale genetic and chemical modifier screens, accelerating the discovery of synthetic lethal interactions and targeted therapy candidates. For further information, please contact Ascent Research.
